RFC 7797 - JSON Web Signature (JWS) Unencoded Payload Option https://tools.ietf.org/html/rfc7797
RFC 7519 - JSON Web Token (JWT) https://tools.ietf.org/html/rfc7519
Abstract JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. The claims in a JWT are encoded as a JSON object that is used as the payload of a JSON Web Signature (JWS) structure or as the plaintext of a JSON Web Encryption (JWE) structure, enabling the claims to be digitally signed or integrity protected with a Message Authentication Code (MAC) and/or encrypted.
JSON Web Signature (JWS) Unencoded Payload Option
Abstract JSON Web Signature (JWS) represents the payload of a JWS as a base64url-encoded value and uses this value in the JWS Signature computation. While this enables arbitrary payloads to be integrity protected, some have described use cases in which the base64url encoding is unnecessary and/or an impediment to adoption, especially when the payload is large and/or detached. This specification defines a means of accommodating these use cases by defining an option to change the JWS Signing Input computation to not base64url- encode the payload. This option is intended to broaden the set of use cases for which the use of JWS is a good fit. This specification updates RFC 7519 by stating that JSON Web Tokens (JWTs) MUST NOT use the unencoded payload option defined by this specification.
RFC 7519 - JSON Web Token (JWT) https://tools.ietf.org/html/rfc7519